Over the past 5 years mobile devices have evolved from devices featuring separate keypads and displays to devices supporting integrated touch-based display screens (i.e. touchscreens). Although touchscreens have been around for a long while, it is the development of low-cost multi-media mobile devices with significant processing capabilities that have validated the utility of touchscreen interfaces and, as a result, account for their widespread popularity. The small screen size of most mobile devices, however, limits the user from taking full advantage of the available processing capabilities (today's smartphones are as powerful as computers in the 90s yet users can't do as much with their phones as they could with an old computer). Phones have gotten smaller, but human fingers have remained the same size. As a result, tasks involving editing, selecting and typing on mobile devices are still cumbersome because finger touch is imprecise (“fat finger/little screen”) and only one or two fingers are typically used at a time. In addition, on small mobile devices, such as smartphones, the on-screen keyboard layout can often cover a majority of the viewable display area. In order to more fully exploit the incredible processing power of the next generation of smart portable electronics, additional types of intuitive user interfaces are needed to complement the functionality of touchscreens in a manner that is also well matched to human sensorimotor capabilities.